1. Field of the invention
The present invention provides an image processing system and related image processing method thereof, and more particularly, to an image processing system and related image processing method capable of make the VBI image clearer.
2. Description of the Related Art
In the past, the cathode ray tube (CRT) displays are major displays. Because the characteristics of the electronic gun, when a field is completely displayed and a next field is to be displayed, the electronic gun needs time to move from the last scan line to the first scan line. Therefore, the TV signal should have an interval between successive fields to provide enough time to the electronic gun to move back to the first scan line.
The above-mentioned interval between the successive fields is called as a vertical blanking interval. The region for transferring pixel data of the field is called as an active region. In general, the VBI of the TV signal does not have to carry any pixel data of the field. Therefore, the VBI can be utilized to transfer some specific data, such as data of teletexts or close caption. The specific data is so-called VBI data.
Please refer to FIG. 1, which is a diagram of a conventional image processing system 100. As shown in FIG. 1, the receiving module 110 comprises a video decoding unit 111, a VBI decoding unit 112, and an image mixing unit 113. The image decoding unit 111 can decode the received TV signal. For example, the TV signal is often a composite signal, and the image decoding unit 111 can perform the Y/C separation on the fields carried by the TV signal to generate a corresponding RGB signal. On the other hand, the VBI decoding unit 112 can decode the VBI data carried by the VBI of the TV signal to generate the OSD to be displayed (which is also transferred as RGB signals.). And then, the image mixing unit 113 can mix the field data decoded by the image decoding unit 111 with the VBI image data decoded by the VBI decoding unit 112. And then, the mixed image data is transferred to the image de-interlacing unit/image scaling unit 115 through the ITU656 interface 114 to perform the de-interlacing or scaling operations. At last, the processed image data is transferred to the display screen (not shown) to display.
For example, the VBI data can carry the above-mentioned close caption. And the image mixing unit 113 can add the decoded close caption into the decoded field such that a new field can be generated. The image de-interlacing unit/image scaling unit 115 can perform de-interlacing/scaling operation and the de-interlaced data are displayed by the display screen.